Improvement in metal-punching machines



2 Sheets-Sheet i.

G. W. VANKHBK.

Metal Punching-Machines.

Patented Aug. 18,1874.

llllllr AH.. Il 1H Ewald.

2 Sheets-Sheet 2. E. W. VANKIRK.

Metal Punching-Machines. NOSAJI, Patented Aug. 18,1874.

PLATE 2 F/G 4- UNITED STATES PATENT OFFICE.

IMPROVEMENT IN METAL-PUNCHING MACHINES.

Specification forming part of Letters Patent No. 154,161, dated August 18, 1874; application filed April 20, 1874.

To all whom it may concern:

Be it known that I, GEORGE W. VANKIRK, ofthe city of Trenton, county of Mercer and State of New Jersey,have invented a new and useful Improvement in Punches for Punching Metals, used in combination with a machine or press driven by power, of which the following is a specification In punching holes for riveting, it is of great importance that the position of the hole should be exactly that intended, so that when two or more plates or pieces are placed together the holes shall perfectly agree. In laying off the position of the holes on the work, the centers are commonly marked by a center-punch, and the punch is formed with a small projecting point at the center of its face. of the same form as the point of the center-punch used in laying off the holes. As this point is, however, necessarily very short, (otherwise it would be broken in use), it is difficult, when the machine is put in motion, and the punch is close down on the plate, to see how nearly the point coincides with themark on the plate or piece being worked, and from the rapid motion of the machine it is impossible to adjust the work satisfactorily.

My improvement consists in substituting for the fixed point on the punch,moving uniformly with the ram of a power-press, a movable point, as shown by the drawings herewith, which shall touch the plate before the face of the punch comes in contact with it, and therefore give longer time for adjusting the work.

Figure I, Plate I, shows the form in which I prefer to construct my improved punch. A hole, A, about one-quarter of au inch in diameter, for punches of the size usual in boiler- Work, is formed in the center of the punch C, and in this, and so fitted as to slide freely, is apiston, B, pointed at the lower end, as previously described, and as shown in the drawings. This piston may either be pressed down by a spring, as shown, or it may simply fall by its own gravity. When the ram of the punching-machine is raised, the point projects below the face of the punch C, so as to just clear the plate, as shown by Fig. IV, Plate II,

and as the ram descends it reaches the plate before the body of the punch. This enables the proper position ofthe plate to be clearly seen, and gives time for -its adjustment.

Whenthe punch commences to form the hole, the piston B is forced up iiush with the face of the punch G, and is therefore exposed to no strain.

I find, in practice, that the punch is not weakened by the hole A bored in its center, nor does the punch become upset so as to cause the piston to stick in the hole. Apparently the hollow punch can be more perfectly hardened than a solid one, and therefore is quite as durable.

Some punching-machines are so constructed that when not forming the hole the ram may be either shortened, or be raised up and thrown out of gear, so that it remains stationary till the plate is in position to be punched. Myimproved punch is equally applicable to these forms of machines, because, when the punch is raised up, the pistou B will project downward sufficiently to enable the plate to be got accurately in position.

I do not confine myself merely to the form ofpunch and pistou as shownin Fig. I, Plate I, but can vary the form, as in Fig. II, Plate I, or other equivalent forms; nor to the construction of press shown in Fig. IV, Plate II, as my improvement is equally valuable and applicable with any form of power machine. I do not, however, claim the sliding point or center-punch when applied to hand-punches, because, in that case, there being ample time for adjustment, the device is of no special importance.

Having thus described my invention so that its advantages will be understood by those skilled in the art, I claim- The combination of a punch provided with a sliding point, B, formed on a separate piston, with a power punching-machine.

GEO. IV. VANKIRK.

Witnesses FRED. J. SLADE, WM. ALLEN SMITH. 

